Not Applicable.
The present invention relates to temperature modification systems, and more particularly to temperature modification systems which use carbon foam composite materials.
Temperature modification systems proliferate today. Homes, offices, cars, trains, and aircraft, for example, all commonly use air conditioning and heating systems for the comfort of occupants.
Certain environments create challenging temperature modification goals for conventional temperature modification systems, such as restrictions on the size and weight of the temperature modification system. Such environments can also demand other modifications, such as a reduction in the level of harmful chemical pollutants and/or particulates. For example, in the automobile racing industry, and in particular NASCAR(trademark), drivers are typically exposed for many hours to hot air having high concentrations of gasoline combustion by-products, including carbon monoxide. As a result, race car drivers frequently complain of fatigue, exhaustion, and dry mouth, symptoms of carbon monoxide (CO) poisoning and heat exhaustion.
A variety of devices have been conceived to provide cool filtered air to race car drivers. However, most are bulky and/or impractical. These devices are usually very simple in design, such as a bucket of ice water, ice, or even dry ice (solidified carbon dioxide), having a copper tube coiled through the bucket. Air is forced by a fan (typically at about 100 cfm) through the copper coil which results in cooling of the air. The cooled air is then filtered and provided to the helmet of the driver in an attempt to cool the driver""s head.
Two problems plague this type of system. First, to supply a bucket of chilled material (e.g. ice) large enough to last the entire race (or even 1 hour) requires a large volume allocated for the cooling system. Second, supplying air to a driver""s helmet in an attempt to cool the head is not an efficient method of cooling an individual since most of the cooled air does not enter the helmet. Poor efficiency results because the helmets are usually fit around a driver""s head. Accordingly, there is generally only a small volume remaining in the helmet for the cooled air to circulate. Hence, the cooling efficiency for individuals using this type of system is generally very low.
Another type of cooling system uses a phase change material (other than ice) or chemical pack (a reaction which is endothermic provides the cooling) in place of the bucket of chilled material. However, this type of system suffers from the same limited cooled air circulation problem inherent when providing cool air to the helmet of an individual.
Other attempts at providing personal cooling systems have targeted developing either complex cooling vests to be worn around the upper torso, or simple cooling vests with ice packs. These systems require the periodic changing of the chilled material or chemical pack. Accordingly, these designs are also generally impractical since they are usually worn under some sort of protective garment (e.g. under a fire suit by auto racers, by firefighters, under protective armor by police, SWAT, and military personnel). Difficulty or inability to change chilled material or chemical packs limits the time individuals can be exposed to harsh environments since changing out the chilled material or chemical packs under protecting garments is prohibitive in most environments (e.g. during a fire or on the 224th lap of a race).
Improved thermal materials have recently been discovered. For example, carbon foam is a material formed from carbon (graphite) fibers which possesses unique properties. Applicant and/or the assignee of the invention (or its predecessors in interest) have invented (or co-invented) processes for forming low density, high thermal conductivity carbon foam materials; e.g., U.S. Pat. No. 6,033,506 to Klett, U.S. Pat. No. 6,037,032 to Klett and Burchell; which are both incorporated herein by reference in their entirety. Through linkage of a plurality of graphitic elements within an appropriate matrix material, carbon foam structures described in the above patents have demonstrated thermal conductivities of approximately 187 W/mxc2x0K, while having densities of only approximately 0.55 g/cc. Thus, carbon foam elements can be produced which are more thermally conductive than aluminum, having approximately ⅕ the weight of an aluminum element having the same volume.
A temperature modification system for modifying the temperature of fluids includes at least one thermally conductive carbon foam element, the carbon foam element having at least one flow channel for the passage of fluids. The flow channel has an inlet and an outlet. At least one temperature modification device is provided, the temperature modification device thermally connected to the carbon foam element and adapted to modify the temperature of the carbon foam, which modifies the temperature of fluid passing through flow channels within the carbon foam.
The temperature modification device can be selected from devices having a first and second side and adapted for reversible operation between two states. A first state, the first side is heated while the second side is cooled. In a second state, the first side is cooled while the second side is heated. Thermoelectric and/or thermoionic elements can provide the above features. In a preferred embodiment of the invention, the temperature modification device can be interposed between two carbon foam elements.
The temperature modification system can include at least one fluid filter, the fluid filter disposed in series with the flow channels. The fluid filter is preferably disposed in direct fluid connection with the flow channel outlet if the outlet temperature is cooler than the inlet temperature. If the outlet temperature is warmer than the inlet temperature, the fluid filter is preferably disposed in direct fluid connection with the flow channel input. The system can also include at least one fluid conduit, such as a hose, for directing temperature modified fluids emitted from the outlet.
A mask can be provided for receiving fluids emitted from the hose, the mask adapted to provide fluids to an individual. In this embodiment, at least one fluid filter can be provided, the fluid filter disposed in series with the flow channel. Preferably, the fluid filter is an activated carbon filter. Preferably, the fluid filter is disposed in direct fluid connection with the flow channel outlet if the outlet temperature is cooler than the inlet temperature. If the outlet temperature is warmer than the inlet temperature, the fluid filter is preferably disposed in direct fluid connection with the flow channel input.
The system can include a control system. The control system can have a polarity switch adapted for switching the sides of the temperature modification device between heating and cooling modes when an appropriate temperature modification device is provided in the system (e.g. thermoelectric, thermoionic).
A method for the reversible temperature modification of fluids includes the steps of providing a temperature modification system including at least one thermally conductive carbon foam element, the carbon foam element having at least one flow channel, and at least one temperature modification device. The temperature modification device is thermally connected to the carbon foam element. A fluid is flowed through the flow channel. The temperature of the fluid emitted from an outlet of the system is modified relative to a temperature of the fluid received at an inlet of the system.
Preferably, the temperature modification device is adapted for switching between heating and cooling modes. Switching between heating and cooling modes can be provided by thermoionic and/or thermoelectric elements. The method can also include the step of filtering the fluid. The fluid filter is preferably disposed in direct fluid connection with the flow channel outlet if the outlet temperature is cooler than the inlet temperature. If the outlet temperature is warmer than the inlet temperature, the fluid filter is preferably disposed in direct fluid connection with the flow channel input.
In another embodiment of the invention, a temperature modification system having a temperature modification device with the ability to heat one side and cool its other side can include a switching manifold. The switching manifold has at least one flow diverting switch for selective transmission of fluids from at least two fluid flows received, a first fluid flow being a heated fluid emitted from an outlet channel which is heated by one of the sides of the temperature modification device, and a second fluid flow being a cooled fluid emitted from an outlet channel which is cooled by the other of the sides of the temperature modification device. The switch can be electronically actuated, preferably provided by a signal transmitted by a thermostat.
The method can also include the step of directing temperature modified fluids which are emitted from the outlet. Temperature modified fluids emitted from the outlet can be supplied to at least one individual. When the temperature modification device provided is adapted for switching between heating and cooling modes, the sides of the temperature modification device can be switched between heating and cooling.
An apparatus having a substantially enclosed volume and a temperature modification system for modifying the temperature of fluids contained within the volume includes at least thermally conductive carbon foam element. The carbon foam element has at least one flow channel for the passage of fluids, the flow channel having an inlet for receiving fluids and an outlet for the emission of fluids, the fluids being received from substantially within the volume. At least one temperature modification device is provided, the temperature modification device being thermally connected to the carbon foam element. The temperature of fluids emitted from the outlet is modified relative to a temperature of fluids received at the inlet.
The enclosed volume can be a vehicle. The vehicle can be a motor vehicle. The motor vehicle can include at least one gas filter, the gas filter disposed in series with the flow channel. The gas filter can be disposed in direct fluid connection with the outlet. The gas filter is preferably disposed in direct fluid connection with the flow channel outlet if the outlet temperature is cooler than the inlet temperature. If the outlet temperature is warmer than the inlet temperature, the gas filter is preferably disposed in direct fluid connection with the flow channel input. In this embodiment, at least one gas conduit such as a hose, can be provided for directing temperature modified fluids emitted from the outlet. A mask can receive gases emitted by the gas conduit. The mask can be adapted to provide temperature controlled and filtered air to at least one occupant of the motor vehicle. The gas filter can be an air filter, the air filter adapted to trap gases including CO.